Lactam polymerization with amide initiators

ABSTRACT

Certain amide compounds based on aromatic amines are utilized as polymerization initiators or activators with alkaline catalysts in the anionic polymerization of lactam monomers so as to provide polymerization systems which may be utilized in a variety of molding operations.

United States Patent [1 1 Matzner et al.

[451 Aug. 28, 1973 LACTAM POLYMERIZATION WlTH AMlDE INITIATORSInventors: Markus Matzner, Edison; Walter T.

Reichle, Millington; Sui-Wu Chow; James E. McGrath, both of Somerville,all of NJ.

Union Carbide Corporation, New York, NY.

Filed: Nov. 11, 1971 Appl. No.: 197,934

Related US. Application Data Division of Ser. No. 183,700, Sept. 24,l97l, which is a continuation-in-part of Ser. No. 26,128, April 6, I970,abandoned.

Assignee:

U.S. CI......L 260/78 L, 260/78 P Int. Cl C08g 20/18 Field of Search260/78 L, 78 P, 26,

References Cited UNITED STATES PATENTS ll/l97l Steinhofer et al 260/78 LFOREIGN PATENTS OR APPLICATIONS l,08l,26l 8/1967 Great Britain 260/78 LOTHER PUBLICATIONS Mottus, E. et al., ACS Polymer Chemistry Div.Preprints, 9(1), pp. 390-397 (1968) Primary Examiner-William H. ShortAssistant Examiner-L. M. Phynes Attorney-Paul A. Rose. James J. OConnellet a].

7 Claims, No Drawings LACTAM POLYMERIZATION WITH AMIDE INITIATORS Thisapplication is a division of patent application Ser. No. 183,700, filedSept. 24th, 1971, which is a continuation-in-part of patent applicationSer. No. 26,128 filed Apr. 6, 1970, said application Ser. No. 26,128being now abandoned.

BACKGROUND OF THE INVENTION 1. Field of the Invention The inventionrelates to the anionic polymerization of lactam monomers.

2. Description of the Prior Art In the anionic polymerization of lactamsthere is usually employed a catalyst-initiator system. The catalyst iscommonly a material which will form an alkali or alkaline earth'metalsalt of the lactam. The initiators or activiators that have been used todate have included a number of materials such as lactones, isocyanatecompounds, acyl lactones, esters and carbonates. Many of theseinitiators, such as diisocyantes, are relatively toxic compounds.

Many of the catalyst-initiator systems also suffer from the disadvantagein that each class of such initiators only provides for either arelatively fast or a relatively slow rate of polymerization. As aresult, each of these classes of initiators is only suitable for use inone or two, but seldom for very many, different types of moldingsystems. Thus, although the relatively slow acting polymerizationsystems are readily useable in rotational casting operations, they arenot too readily useful in extrusion molding processes or in other typesof casting operations. The fast acting initiators, on the other hand,although useful in extrusion processes and in some casting operations,are not readily useful in rotational casting operations. As a result, itis necessary, in many cases, to use a different catalyst-initiatorsystem in differnent molding processes.

SUMMARY OF THE INVENTION system in a variety of molding operations.

Another object of the present invention is to provide a novel initiatoror activator system for use in the anionic polymerization of lactammonomers.

DESCRIPTION OF THE PREFERRED EMBODIMENT It has now been found thatlactams may be polymerized anionically with a catalyst-initiator systemthat may be employed in a variety of molding operations if there isemployed as such catalyst-initiator system an anionic catalyst, and, asan initiator or activator, one or more of certain aromatic amine basedamide compounds.

THE LACTAMS The lactams which may be polymerized according to thepresent invention are all those which are capable of being polymerizedanionically and are preferably those lactam monomers which contain atleast one ring group of the structure wherein n is a whole number whichis 3 to 15, and preferably 3 to 10, and R and R, may be the same ordifferent radicals on each carbon atom and may be H or C to Chydrocarbon.

Such lactams would include those having a single ring structure such as2-pyrrolidone, 2-piperidone, 6-methwherein n' and n" are each wholenumbers such that n' and n" is 2 to 14-, R and R are as defined above;and R may be C to C alkylene such as methylene, ethylene, propylene andbutylene; phenylene and substituted phenylene; O and S.

Other lactams having a plurality of ring structures include bicycliclactams, such as those represented by the The lactams to be polymerizedcan be used individually or in any combination thereof.

THE INITIATOR The initiator which is to be employed in the presentinvention is a compound having the structure ll P-R".

n is a whole number of about 1 to 10 inclusive, R is a C, to Cinclusive, saturated or unsaturated, substituted or unsubstituted,carbon containing radical which may be a) a hydrocarbon radicalincluding aliphatic, alicyclic and aromatic radicals such as methyl,ethyl, propyl, butyl, cycloheptyl, cyclohexyl, allyl, propenyl,hexadienyl, octadienyl, phenyl, benzyl and naphthyl, and/or b) a radicalcontaining 0, S, and/or N in the carbon chain such as 2-pyridyl,3-quinolyl, and 2-oxazolyl; and R, and R" may be the same or differentand may be H or R, and where R, R and R" are substituted carboncontaining radicals, they may contain substituents which are inert tothe other components of the polymerization reaction system, such ashalogen, i.e., Cl, Br, F, and l, NO and CN. R and R may also be bondedtogether to form a cyclic structure with N and X, and in such case R Rmay be [CR,R ]n wherein R and R may be the same or different and may beas defined for R and R" above, and n is a whole number which is 3 toabout 20 inclusive.

The electron withdrawing groups with which the Ar radical may besubstituted include halogen (i.e., Cl, Br, F and l) radicals, CN, CFSO,R"', COR', NO, CCl; PO(R"' and SOR', wherein R"' is as defined for Rand R" above. In the PO(R"') group only one R' may be H.

ln some of the initiators as noted above, the Ar radical may contain twoor more homocyclic rings which are not fused together. In suchinitiators the non-fused rings may be joined together by a covalentbond, or by one or more linking groups which may be k @or V wherein R isas defined above.

Examples of the substituted Ar radicals in the polyamides would includeR' is as defined above, and

Y S0, S0,, C0, CF CCl C(CN) or POR wherein R' is as defined above.

The initiators of the present invention may be used individually, or incombination with one or more of each other, or with other initiators.About 0.2 to 10, and preferably 0.5 to 5, mole per cent of initiator isemployed based on the moles of'lactam being polymerized.

THE POLYMERS The use of the initiators of the present invention re sultsin the preparation of polymers by the following two step procedure, inwhich the use of a monoamide initiator is shown:

anion again regenerated.

The last two steps are repeated many times and result in a polymerhaving the structure wherein Ar, X, R and R are as defined above, M isthe cation of the anionic catalyst, and R is that portion of thestructure of the lactam being polymerized which lies between thenitrogen atom and the carbonyl carbon atom of such lactam, and

m is a whole number which is 1 and is such that the polymer is amaterial, that is normally solid, i.e., solid at temperatures of about25 C., and has a reduced viscosity in m-cresol (0.1 gram/100 ml) at 25C. of 2 0.4, and preferably about 0.8 to 7, deciliters/gram.

The value of m may vary somewhat in each polymerized lactam chain, andwill be about to about 5,000. The polymers would thus have molecularweights of about 1,000 to 500,000 or more.

The lactam polymers prepared with the amide initiators of the presentinvention have good physical properties.

THE CATALYST The catalysts which may be employed in the anionicpolymerization reaction of the present invention include all anioniccatalyst materials which may be employed in the anionic polymerizationof lactams The catalyst material is usually a salt of the lactam beingpolymerized although any other lactam may be used to form the catalyst.The salt is usually prepared by reacting the lactam with a strong base,i.e., a base strong enough to convert the lactam to its salt. Such baseswould include alkali and alkaline earth metals or basic derivatives ofsuch metals such as the hydroxides, oxides, alkoxides, phenoxides,hydrides, alkyls, aryls, amides, borohydrides and weak acid salts, i.e.,acetates, carbonates, bicarbonates, benzoates, sulfites and bisulfites;Grignard reagents, and various other organometallic compounds. Suchbases would include, therefore, metals such as lithium, sodium,potassium, magnesium, calcium, strontium, barium, and aluminum andderivatives of such metals, such as lithium hydroxide, sodium hydroxide,potassium hydroxide, magnesium hydroxide, calcium hydroxide, strontiumhydroxide, barium hydroxide, lithium hydride, sodium hydride, sodiumoxide, sodium methoxide, sodium phenoxide, sodium methyl, sodium ethyl,sodium phenyl, sodium naphthyl, and sodamide; Grignard reagents such asethyl magnesium chloride, methyl magnesium bromide, and phenyl magnesiumbromide; and other compounds such as zinc diethyl, triisopropylaluminum, diisobutyl aluminum hydride, and lithium aluminum hydride.

About 0.2 to 20, and preferably 0.5 to 6 mole per cent of catalyst isused per mole of monomer being polymerized.

The catalyst and initiator are employed in a mole ratio to each other ofabout 2 to 20, and preferably, 3 to 12.

When the strong base is reacted with the lactam to form the catalyst aby-product is usually formed. For example, hydrogen is formed as aby-product when the metal hydrides or the elemental metals are used;water is formed as a by-product when metal hydroxides are used; alcoholsare formed when alkoxides are used and water and CO are formed whencarbonate or bicarbonate salts are used. The preferred catalysts arethose which result in the most readily removable byproducts, since someof the by-products, such as H O, may have a deleterious effect on thepolymerization reaction.

THE POLYMERIZATION PROCESS The polymerization reaction is preferablyconducted in bulk. Under such bulk polymerization procedures themonomer, catalyst and initiator are charged in the desired proportionsto the reactor. The bulk polymerization reaction is usually conducted atatmospheric pressure and at a temperature of about to 250C. The reactioncan be conducted at a temperature which is above or below the meltingpoint of the resulting polymer, and above that of the monomer. The useof elevated pressure is not required for the polymerization reaction.The bulk polymerization reaction requires a polymerization period ofabout 3 to 15 minutes at 100-250 C, depending on the lactam(s) employed,and the polymerization temperature. The bulk polymerization reactionshould be carried out under anhydrous conditions, i.e., in the presenceof no more than about 0.3 weight per cent, and preferably no more than0.03 weight per cent, of water or other active hydrogen containingby-product. Where a catalyst is used which would generate water or otheractive hydrogen containing by-products, such as the hydroxide, alkoxideor phenoxide catalysts, the excess amounts of such byproduct materialsshould be removed before the polymerization reaction is conducted.

The polymerization is preferably carried out under an inert blanket ofgas, such as, nitrogen, argon or helium in order to prevent oxidativedegradation of the monomer and destruction of the catalyst by moisture.

The reaction may be carried out batchwise or continuously. Anadvantageous method of carrying out the reaction of the presentinvention is to conduct the bulk polymerization in conventional moldingequipment such as a rotational casting device or a compression moldingmachine, or an extruder. In" this way the polymer and the molded objectscan both be formed in one step. Where the polymerization is conducted insuch molding devices, conventional molding pressures may be employed inorder to simultaneously form the molded object with the in situ formedpolymer.

Since the lactams are normally solid materials at room temperatures, thebulk polymerization reactions may be carried out by various procedures.In one procedure, the lactam may be melted, and both the catalyst andthe initiator admixed with it and then the reaction may be caused toproceed by bringing the reaction mixture to polymerization temperatures.

In another procedure, the catalyst and initiator may be dissolvedseparately in the lactam monomer, after which the two separate solutionsmay be combined to cause the polymerization to proceed at polymerizationtemperatures. Where the polymerization is conducted in moldingequipment, the equipment may be heated to the desired polymerizationtemperature in order to effect polymerization upon injection therein ofthe polymerization reaction system.

In addition to being conducted in bulk, the polymerization may also beconducted in high boiling inert organic solvents, i.e., those havingboiling points of about 100 C., such as chlorobenzene, dichlorobenzene,xylene, trichlorobenzene, dirnethyl sulfoxide, N-alkyl pyrrolidones andhexamethylphosphoramide at temperatures of about 100 C. up to theboiling point of the solvent; or at temperatures of about to 240 C. indispersion systems such as those disclosed in US. Pat.

Nos. 3,061,592 and 3,383,352, by G.B. Gechele and G.F. Martins in J.Applied Polymer Science 9, 2939 (1965).

ADJUVANTS The polymerization reaction of the present invention may alsobe conducted in the presence of various types of adjuvant materialswhich are normally employed with the types of polymers prepared by thepresent invention, or the adjuvants may be added to the polymer after itis formed. Such adjuvant materials would include fillers, stabilizers,fibrous reinforcing agents such as asbestos and glass fiber, andpigmenting materials.

The particular polymer being prepared as well as the end use applicationwill dictate the selection and quantity of the adjuvant to be employedtherewith since it is the respective adjuvants for such polymers andsuch applications that are to be employed in the present invention. Theadjuvants employed must be physically and chemically compatible witheach of the other components of the monomer and polymer basedcompositions, under the prescribed operating conditions. As such, wherethey are present during the polymerization reaction, the adjuvantsshould not contain reactive groups which would interfere with thepolymerization reactions, such as active hydrogen containing groups suchas carboxyl, amino, mercaptan or hydroxyl groups.

The adjuvants would be used in amounts which would be effective forintended purpose. Thus, a stabilizer would be used in a stabilizinglyeffective quantity, and the fillers would be used in effectivequantities therefor. For example, if a reinforcing filler were to beused, such filler should be used in such amounts as to provide thedesired reinforcing effect.

The polymers made by the process of the present invention may be usedfor a number of applications which require the use of molded articlesprepared from lactam polymers such as fibers, films, engineeringstructures, coatings and hollow articles such as tubing and solventtanks.

The following examples are merely illustrative of the present inventionand are not intended as a limitation upon the scope thereof.

EXAMPLE 1 Preparation of N,Ni'-dimethyl-N,N-diacetyl-4,4'-diaminodiphenyl sulfone, i.e.,

CH CH;

500 grams (1.74 mole) of 4,4- dichlorodiphenylsulfone, 5.0 grams ofcuprous chloride and 1,200 ml of 40 percent aqueous methylamine 14.2mole) were heated in a 2.2 liter titanium-lined bomb for 18 hours at250C. After cooling, the slurry was filtered, the solids washed twicewith cold water and dried (75/vacuum); yield 472 g.; 98 percent oftheory. The product melted at l63-l73 C. Crystallization of a smallsample from ethanol yielded the N,N'- dimethylamine compound with a M.P.of l75l77 C.

50 grams of the diamine were refluxed overnight in 50 ml. of glacialacetic acid and 50 ml. acetic anhydride. The solvent was then evaporatedand the desired diamide product was crystallized from 500 ml of 80aqueous ethanol; m.p. l557 C.

EXAMPLE 2 Preparation of N,N'-dimethyl-N,N'-trifluoroacetyl-4,4'-diaminodiphenyl sulfone, i.e.,

10 grams of the N,N-dimethylamine compound prepared as in Example 1 wererefluxed in 35 ml. of trifluoroacetic acid and 15 ml. of the anhydrideof trifluoroacetic acid. The desired trifluoroacetyl derivative thusproduced was crystallized from ethanol, melting point: l60.0l6l .5 C.

EXAMPLE 3 Preparation of Nmethyl-2,4,o-trichloroacetanilide, i.e.,

C H: C CH:

28.6 grams (0.27 mole) of N-methylaniline were chlorinated at l0l8 in 114 ml. of acetic acid with 60 grams (0.84 mole) of C1 Following this, 56grams of acetic anhydride (0.55 mole) were added and the liquid systemwas refluxed over night. The volatiles were removed and the residuecharcoaled and crystallized from 25 percent aqueous ethanol, to provide8.3 grams of the desired compound which had a melting point (M.P.) of -7C.

EXAMPLE 4 Anionic polymerization of e-Caprolactam using N,N'-dimethyl,N,N'-trifluoroacetyl, 4,4- diaminodiphenyl sulfone as the initiatorMolten e-caprolactam (28.3 grams, 0.25 mole) was added to twocylindrical 25 mm X 200 mm glass tubes (total monomer charge was 56.6grams or 0.5 mole). Both tubes were heated in a C. oil bath. Sodiumhydride (0.48 grams, 2 X 10- mole, as 0.84 grams of a 57 percent mineraloil dispersion, 4 mole percent based on the total monomer) was added toone tube. It quickly reacted to form a homogeneous solution of sodiume-caprolactam in e-caprolactam.

Initiator (1.0 grams, 2.14 X 10 mole, 0.42 mole percent based on thetotal monomer) was added to the second test tube. After a solution wasformed in this test tube and the temperatures of the two solutions wereequilibrated at the bath temperature, the two solutions were mixed andheated in the bath. The progress of the polymerization was followedvisually. The polymer viscosity was higher after 7 minutes.Crystallization started at 18 minutes. The polymer was removed from thebath after 10 minutes. The properties of the polymer were as follows:reduced viscosity 1.29 dl/gm., methanol extractables 2.86, tensilemodulus 308,000

psi, tensile strength 10,000 psi, elongation at break 30 percent andpendulum impact 253 ft. lb./in.

EXAMPLES -9 Anionic polymerization of e-caprolactam using N,N'-dimethyl-N,N'-diacetyl-4,4'-diaminodiphenyl sulfone as the initiator.

A series of five polymerization reactions were conducted. In each of thefive examples each of two 25 X 200 mm test tubes were charged with 28.3grams (0.25 mole) of molten e-caprolactam and both test tubes were thenheated at the desired polymerization temperature. Sodium hydride in theform of a 57 percent dispersion in oil was added to one of these testtubes while the initiator was added to the other. After solutions wereformed and equilibrated with the bath temperature they were mixed, andthen heated at the desired polymerization temperature. The progress ofthe polymerization was followed visually. The polymer that formed wasground up and extracted with methanol in a Soxhlet extractor for 25hours to determine the per cent of extractables (monomer and oligomers).The amounts of catalyst and initiator used and the polymerizationconditions and results are summarized below in 10 27.6 g. (0.1 mole) ofbis-(N-methyl-paminophenyl)sulfone in ml. of pyridine. A mild exothermwas noted. When the exotherm ceased, the reaction solution was heatedunder reflux for twenty-four hours. The solution was poured into waterand the bisbenzamide was separated from the .water by extraction withchloroform. The chloroform solution was evapo;

rated, and the residue was recyrstallized successively fromchloroform-carbon tetrachloride (1:2) and 20 percent aqueous ethanol.There was obtained 27 g. of the bis-benzamide, m.p. 128, nmr spectrumexhibited chemical shifts (TMS, in CDCl;,) at 7.71, 7.20, 7.15 foraromatic protons and 3.45 ppm for N-CH group, with total aromatic proton.to N-Cl-l area ratio of 2.94 to l (theory 3 to l). Elemental Analysisvalues for C I-1 11 0 8:

Calculated: S- 6.62; N-5.78

Found: 8- 6.49; N-5.77

EXAMPLE 14 Polymerization of e-caprolactam using the diamide compoundprepared as in Example 13 as an anionic polymerization initiator.

into each of two 25 X 200 mm test tubes was added Table l for each ofthe five examples. 25 28.3 g. (0.25 mole) of molten caprolactam and bothTABLE I Inititfmin.) Nall ator Polym. heating Percent, RV., mole, mole,temp., t(min.) dlsconcxtraet- 1101, (11.! percent percent C. crystal.tinued ahle C. gm.

Fxample 5 2 0.5 160 2 4 6.0 71.2 1.8 (i 2 0.7 160 1.5 4 7.1 1.8 7 2 0.53 5 5. J 80. 8 1. 3 8 .2 0.7 140 2.5 5 7.2 1.4 J 4 0.56 165 l 11.4 1.52

A lilm of modulus 297,000 p.s.i., tensile strength 9,700, elongation atbreak 70% pact 159.

NOTE: IlDT=heat distortion temperature.

EXAMPLES 10-12 N-methyl-2,4,6-trichloroacetanilide as initiator for thepolymerization of e-Caprolactam A series of three polymerizationreactions were conducted. ln each of the three examples the generalpolymerization procedure used is the same as that described in Examples'5-9, except that N-Methyl-2,4,6- Trichloroacetanilide was used as theinitiator. The amounts of the catalyst and initiator that were used andpolymerization conditions and results are summarized below in Table 11for each of the three examples.

0 C. Two (2) mole percent ofa the extracted polymer was compressionmolded at 250 C. and it had tensile and pendulum imwere then heated at apolymerization temperature of catalyst, sodium hydride, in the form of adispersion (57 percent) in oil was added to one of these test tubes,while 1.0 mol percent of the initiator was added to the other. Aftersolutions were formed and equilibrated with the bath temperature, theywere mixed and then heated at the 160 C. polymerization temperature. Theprogress of the polymerizatiori was followed visually. The time requiredfor the development of opacity was taken as the time required forcrystallization of the nylon-6 formed.

TABLE II Initit(mln.)

NaH ator Polym. heating Percent, RV.,

mole, mole, temp., t(min.) disconextraet- HDT, dl./

percent percent C. crystal. tinued able C. gm.

Expt.

EXAMPLE 13 The no-flow time for the polymerization system was A solutionof 56 g. (0.4 mole) of benzoyl chloride in 50 ml. of pyridine was addedslowly to a solution of one minute and the time required forcrystallization was 1.5 minutes.

EXAMPLE 15 Preparation of p-phenyl sulfonyl-N-methyl N-methylacetanilide, i.e.,

A mixture of 25 g. (0.1 mole) of phenyl pchlorophenyl sulfone, 75 ml. of40 percent aqueous methylamine, and 0.25 g. of cuprous chloride washeated at 250 in a rocker bomb for 24 hours The re sulting aminatedsulfone was isolated by washing with water until methylamine odor wasonly faintly detectable. To the crude aminated sulfone there was thenadded 100 ml. of acetic anhydride and the mixture was heated at refluxfor 24 hours.

Excess acetic anhydride was then evaporated from the reaction system andthe residue was poured into water. The amide was collected andrecrystallized from 20 percent aqueous ethanol. There was obtained 17.8g. of the desired amide which had a melting point of l30-l32.

EXAMPLE l6 Polymerization of e-caprolactam using the amide compoundprepared as in Example as an anionic polymerization initiator.

lnto each of two 25 X 200 mm test tubes was added 28.3 g. (0.25 mole) ofmolten caprolactam, and both were then heated at a polymerizationtemperature of 160 C. Two (2) mole percent of a catalyst, sodiumhydride, in the form of a dispersion (57 percent) in oil was added toone of these test tubes, while 0.5 mole percent of the initiator wasadded to the other. After solutions were formed and equilibrated withthe bath temperature, they were mixed and then heated at the 160 C.polymerization temperature. The progress of the polymerization wasfollowed visually. The time required for the development of opacity wastaken as the time required for crystallization of the Nylon 6 formed.

The no flow time for the polymerization system was 1 to 1.5 minutes, andthe time required for crystallization was 1.5-2 minutes.

EXAMPLE 17 Preparation of N,N'-dimethylsulfonyl-N,N-dimethyl-4,4'-diamino diphenyl sulfone, i.e., (11: on;

A solution of 33 g. (0.4 mole) of methanesulfonyl chloride in 50 ml. ofpyridine was added dropwise to a solution of 27.6 grams (0.1 mole) ofbis(N-methyl-paminophenyl)sulfone in 100 ml of pyridine over a period ofabout 15 minutes. After the mild exotherm subsided, the mixture washeated at reflux for 22 hours. The reaction mixture was poured intowater and the precipitated product was washed with water andrecrystallized from chloroform. There was obtained 24.5 g. of thedesired sulfonamide which had a melting point of 213215 C.

Anal: Calc. for C,,H, N,O,S,: C, 44.43; H, 4.60; N, 6.48; 8, 22.23 FoundC, 43.92; H, 4.37; N, 6.34; S, 2238 EXAMPLE l8 Polymerization ofe-caprolactam using the diamide compound prepared as in Example 17 as ananionic polymerization initiator.

lnto each of two 25 X 200 mm test tubes was added 28.3 g. (0.25 mole) ofmolten caprolactam, and both wree then heated at a polymerizationtemperature of 160 C. Two (2) mole percent of a catalyst, sodiumhydride, in the form of a dispersion (57 percent) in oil was added toone of these test tubes, while 1.0 mole percent of the initiator wasadded to the other. After solutions were formed and equilibrated withthe bath temperature they were mixed and then heated at the 160 C.polymerization temperature. The progress ofv EXAMPLE 19 A. Preparationof (N-methyl-paminophenyl)diphenyl phosphine oxide, i.e.,

Twenty (20.0) grams of (p-chlorophenyl)diphenyl phosphine oxide, i.e.,

were heated in a 220 ml titanium lined bomb at 250 C. for 18 hours with120 ml of 40 percent aqueous methylamine, (CH,NH,). The temperature ofthe reaction was then quenched to room temperature and the contents ofthe bomb were transferred to a 500 ml beaker to which 200 ml of waterwere added. The system was heated at C. for about 1 hour to removevolatile material. The resulting system was then washed several timeswith water to remove CH NH -Hcl and the product was dried. There wasobtained 18.3 grams of the product (93 percent of theory). A 5 gramsample of the product was then crystallized twice from 50/50benzenelcyclohexane to yield 4.1 grams of(N-methyl-paminophenyl)dipheny1 phosphine oxide. This product had amelting point of l77l 78 C. Analysis for C H PON:

Calculated: C, 74.27; H, 5.86; N, 4.56

Found: C, 75.34; H, 6.00; N, 4.15

The infrared spectrum of the compound showed N-H,

CH: O

13 .3 grams of the (N-methyl-paminophenyl)diphenyl phosphine oxideprepared above in Example 19A and 4.42 grams of acetic acid anhydridewere admixed in 100 ml of glacial acetic acid and then refluxed for 45minutes. The volatile components of the system were then evaporated at100 C. The residual acetic acid was displaced with toluene twice, at 50C (25-50 mm Hg). The yield (crude) of the desired product was 12.5 gramsor 83 percent of theoretical. When crystallized from 50/50benzene/cyclohexane and then from 50/50 benzene/ethyl ether. the producthad a melting point of 148-149 C. Analysis for C H O PN Calculated: C,72.21; H, 5.73; N, 4.01 Found: C, 72.15; H, 5.42; N, 4.13

absorptions, next to monosubstituted phenyl and paradisubstituted phenylabsorption bands. The nmr analysis of the compound showed aryl-l-ly]CHag:

N-Cl-l -H ratios of 4.95 1 1 (theory 4.68 1 l).

EXAMPLES 20-22 Polymerization of e-caprolactam using the amide compoundprepared in Example 193 as an anionic polymerization initiator.

A series of three polymerization reactions were conducted. ln each ofthe three examples each of two 25 X 200 mm test tubes were charged with28.3 grams (0.25 mol) of molten e-eaprolactam and both test tubes werethen heated to a temperature of 150 C. Sodium hydride in the form of a57 percent dispersion in oil was then added to one of these test tubeswhile the initiator was added to the other. After solutions were formedin each of the test tubes and equilibrated with the 150 C. bathtemperature, the contents of the two test tubes were mixed, and heatedin the 150 C. bath. The progress of the polymerization was followedvisually. The time required for the development of opacity was tkaen asthe time required for crystallization of the nylon-6 polymer that wasformed. The amounts of catalyst and initiator that were used (mole%) andthe crystallization time required in each experiment are summarizedbelow in Table 111 for each of the three examples.

TABLE 111 Nail initiator Crystal. time Example mole% mole% (minutes) 20Z 1 -6 21 4 2 3-4 22 4 Z 4-5 EXAMPLE 23 Preparation of N,N'-formylN,N'-methyl-4,4'-

diamino diphenyl sulfone, i.e.,

EXAMPLE 24 Polymerization of e-caprolactam using the compound preparedas in Example 23 as an anionic polymerization initiator.

Into each of two 25 X 200 mm test tubes was added 28.3 grams (0.25 mol)of molten e-caprolactam and both were then heated at a temperature of150 C. Two (2) mole% of a catalyst, sodium hydride, in the form of adispersion (57%) in oil was added to one of these test tubes, while 0.5mole% of the initiator was added to the other. After solutions wereformed in each of the test tubes and equilibrated with the 150 C. bathtemperature, they were mixed and then heated at 150 C. The progress ofthe polymerization was followed visually. The time required for thedevelopment of opacity was taken as the time required forcrystallization of the ny- Ion-6 that was formed. The time required forcrystallization was l5-l7 minutes.

EXAMPLE 25 Preparation of N,N'-diphenylphosphoryl-N,N'-dimethyl-4,4-diamino diphenyl sulfone, i.e.,

9 cu. 1n; 0

A solution of 9 grams (3.8 millimols) of diphenylphosphoryl chloride and5.25 grams (1.9 millimols) of bis(p-methylaminophenyl) sulfone in 100 mlof pyridine was heated at reflux for 16 hours. The reaction mixture wasthen evaporated to dryness under aspirator pressure. The resultingresidue was then extracted with benzene. Upon evaporation of the benzenefrom the extract there was obtained 9.8 grams (80 percent oftheoretical) of N ,N '-diphenylphosphoryl-N,N dimethyl-4,4'-diaminodiphenyl sulfone in crude form which had infrared absorptions at 7.5,8.6p. (for S0 7.7;; (for P0); and a triplet at 13.25, 13.7 and 14.4;1. ss)z EXAMPLE 26 Polymerization of e-caprolactam using the compoundprepared as in Example 25 as an anionic polymerization initiator.

Into each of two 25 X 200 mm test tubes was added 28.3 grams (0.25 mole)of molten e-caprolactam and both test tubes were heated to 160 C. Four(4) mole percent of a catalyst, sodium hydride, in the form of adispersion (57 percent) in oil was added to one of these test tubes,while 1.0 mole percent of the initiator was added to the other. Aftersolutions were formed in each of the test tubes and equilibrated withthe 160' C. bath temperature, they were mixed together and then heatedat 160 C. The progress of the polymerization was followed visually. Thetime required for the development of opacity was taken as the timerequired for crystallization of the nylon-6 polymer that was formed.

The no-flow time for the polymerization system was 3 minutes and thecrystallization time was about 30 minutes.

PREPARATION OF THE lNlTlATORS The initiators used in the process of thepresent invention may be prepared as disclosed in some of the aboveexamples and as disclosed in several United States Patent applications,i.e., Halogenated Diamino Diphenyl Sulfone Derivatives" filed Apr. 6,1970 as Ser. No. 26,056, now abandoned and refiled Dec. 6, 1971 as C-l-P205,322 in the name of W. T. Reichle, and

Aromatic Acid Diamides of Diamino Diphenyl Sulfones,"Monoamides ofMonoamino Diaryl Sulfones," and Disulfonamides of Diamino DiphenylSulfones," which latter three applications were filed Apr. 6, 1971 inthe names M. Matzner, W.T. Reichle, S.W. Chow and LE. McGrath as Ser.No. 26,053, now US. Pat. No. 3,696,131; 26,057, now US. Pat. No.3,696,132 and 26,045, now US. Pat. No. 3,718,672 respectively. Thedisclosures of all of such applications are incorporated herein byreference.

The initiators of the present invention are prepared by reacting anamine compound of the structure ir-l.

wherein Ar, R and n are as defined above, with at least a molarequivalent, and preferably a molar excess, of a compound having thestructure wherein X and R. are as defined above, and a is l or 2, andwhen a is l, A is OH or a halogen radical, i.e., Cl, F, Br or 1, andwhen a is 2, A is an O radical. When A is a halogen radical, halogenacid is formed as a byproduct when A is an OH radical, water is formedas a by-product, and when A is an O radical, an acid is formed as aby-product. When a halogen acid is formed as a by-product the reactionsare preferably conducted in a halogen acid accepting solvent such aspyridine, alkyl substituted pyridines and triethylamine. At least onemole of such acid accepting solvent is used per mole of halogen acidformed in the reaction. Excess solvent may be used for diluent purposes.

When water is a by-product, the reaction system preferably containsmechanical or chemical means for effectively removing the water so thatthe reaction may be driven to completion.

The reaction is conducted at atmospheric pressure and at temperatures ofabout 80 to 200 C. The preferred temperature is the reflux temperatureof the mixture of the components of the reaction system. The reactionmay be run under an inert blanket of a moisture free gas such asnitrogen. The reaction is usually conducted for a period of up to about24 hours.

The initiator compounds are crystalline materials which may be readilyrecovered from the reaction systems in which they are prepared byprecipitation with water or by extraction with solvents such aschloroform, benzene and toluene followed by crystallization fromappropriate solvents such as chloroform, aqueous ethanol or aqueousacetone, benzene, cyclohexane, ethyl ether and hexane.

The initiators prepared in Examples 1, 2, and 23 are representative of asubclass of initiators wherein, n, as defined above, is 2, X, as definedabove, is

and, R, as defined above is H or a C, to C inclusive, hydrocarbon orperhalocarbon radical. The preferred of such R' radicals are aliphaticradicals.

The initiators prepared in Example 15 and 19B is representative ofinitiators wherein n, as defined above,

is l, X, as defined above, is I c.

and R, as defined above, is a C, to C inclusive, hydrocarbon radical.

The initiator prepared in Example 17 is representative of initiatorswherein n, as defined above, is 2, X, as defined above is 50,, and R, asdefined above, is a C, to C inclusive hydrocarbon radical.

The initiator prepared in Example l3 is representative of initiatorswherein n, as defined above is 2, X, as defined above, is

ll C,

and the two R's, as defined above, are the same or different mono-orpolynuclear aromatic radicals. These aromatic radicals may beunsubstituted, or substituted with one or more inert substituents. Wherethese aromatic radicals contain a plurality of phenyl rings, the ringsmay be fused together, or bonded together through a single covalent bondor through an intervening polyvalent inorganic or organic radical. Thepreferred of these aromatic radicals are substituted or unsubstitutedphenyl and naphthyl radicals.

The initiator prepared in Example 25 is representative of initiatorswherein n, as defined above, is 2, X, as defined above, is

and R, as defined above, is a C, to C inclusive, hydrocarbon radical.

We claim:

1. In an improved process for anionically polymerizing lactam monomerhaving 4 to 16 annular carbon atoms in each ring structure thereof withanionic lactam polymerization catalyst and anionic lactam polymerizationinitiator to produce moldable polyamide resin, the improvement whereinsaid initiator is at least one compound having the structure wherein Yis S0 or $0,,

n is a whole number of l to about 5, inclusive, and

R, R and R" are C, to about C inclusive, hydrocarbon radicals.

2. A process as in claim 1 in which Y is S0,.

3. A process as in claim 2 in which the two Rs are the same.

4. A process as in claim 3 in which R is phenyl.

5. A process as in claim 4 in which said initiator comprisesN,N'-diphenyl phosphoroso-N,N'-dimethyl-4,4'- diamino diphenyl sulfone.

6. A process as in claim 1 in which said lactam monomer comprises Ecaprolactam.

7. A process as in claim 1 which is conducted in a shaping device withthe simultaneous formation of a shaped article.

2. A process as in claim 1 in which Y is SO2.
 3. A process as in claim 2in which the two R''s are the same.
 4. A process as in claim 3 in whichR'' is phenyl.
 5. A process as in claim 4 in which said initiatorcomprises N, N''-diphenyl phosphoroso-N,N''-dimethyl-4,4''-diaminodiphenyl sulfone.
 6. A process as in claim 1 in which said lactammonomer comprises E - caprolactam.
 7. A process as in claim 1 which isconducted in a shaping device with the simultaneous formation of ashaped article.